Vehicular camera with thermal compensating means

ABSTRACT

A vehicular camera includes a camera housing having a first portion and a second portion joined to the first portion. The first portion of the camera housing accommodates a lens and has an attaching portion having a first coefficient of thermal expansion (CTE). A circuit board includes circuitry disposed at a circuit board substrate that has a second CTE that is different from the first CTE. The circuitry includes an imager. The circuit board substrate is attached at the attaching portion of the first portion of the camera housing. When the vehicular camera is operated at an operating temperature greater than 50 degrees C., the attaching portion expands a greater degree than the circuit board substrate. When the vehicular camera is operated at an operating temperature below −20 degrees C., the attaching portion contracts a greater degree than the circuit board substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 17/248,628, filed Feb. 1, 2021, now U.S. Pat. No. 11,343,414,which is a continuation of U.S. patent application Ser. No. 16/680,658,filed Nov. 12, 2019, now U.S. Pat. No. 10,911,647, which claims thefiling benefits of U.S. provisional application Ser. No. 62/758,723,filed Nov. 12, 2018, which is hereby incorporated herein by reference inits entirety.

FIELD OF THE INVENTION

The present invention relates generally to a vehicle vision system for avehicle and, more particularly, to a vehicle vision system that utilizesone or more cameras at a vehicle.

BACKGROUND OF THE INVENTION

Use of imaging sensors in vehicle imaging systems is common and known.Examples of such known systems are described in U.S. Pat. Nos.5,949,331; 5,670,935 and/or 5,550,677, which are hereby incorporatedherein by reference in their entireties.

SUMMARY OF THE INVENTION

The present invention provides a driver assistance system or visionsystem or imaging system for a vehicle that utilizes one or more camerasto capture image data representative of images exterior of the vehicle,and provides a means for accommodating different degrees of thermalexpansion and contraction of the circuit board relative to the lensholder (due to the circuit board having a coefficient of thermalexpansion (CTE) that is different from the CTE of the lens holder orstructure at which the circuit board is mounted). When the camera isdisposed at the vehicle and exposed to a higher or lower temperature(such as, for example, greater than 40 degrees C. or less than 0 degreesC.), the circuit board and support structure accommodate the differentdegrees of expansion and contraction such that the circuit board remainsplanar or non-flexed and such that an imaging plane of the imagerdisposed at the circuit board remains orthogonal or normal to theoptical axis of the lens. For example, the circuit board may be attachedat the support structure via fasteners that are received throughoversized holes in the circuit board substrate, or the circuit board maybe attached at the support structure via a plurality of spaced apartposts that are radially flexible to flex toward or away from an opticalaxis of the lens or lens assembly.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a vehicle with a vision system thatincorporates cameras in accordance with the present invention;

FIG. 2 is a sectional view of a camera with a circuit board attached ata lens holder;

FIGS. 3 and 4 are sectional views of the camera of FIG. 2 , showingbending of the circuit board when the camera is exposed to low and hightemperatures;

FIG. 5 is a sectional view of another camera with a circuit boardattached at a lens holder via at least one oversized fastener hole;

FIGS. 6 and 7 are sectional views of the camera of FIG. 5 , showing theexpansion/contraction of the circuit board being accommodated by theoversized hole(s) so that the circuit board does not bend or flex;

FIG. 8 is a sectional view of another camera with a circuit boardattached at a lens holder via elongated posts;

FIGS. 9 and 10 are sectional views of the camera of FIG. 8 , showing theexpansion/contraction of the circuit board being accommodated by flexingof the posts;

FIGS. 11 and 12 are perspective views showing an exemplary design of theposts, which allow for flexing in one direction and limit flexing inanother direction orthogonal to the one direction; and

FIGS. 13-15 are perspective and partial sectional views of another lensholder and posts configuration, showing an adjustable post configurationto achieve athermalization tuning of the camera.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A vehicle vision system and/or driver assist system and/or objectdetection system and/or alert system operates to capture images exteriorof the vehicle and may process the captured image data to display imagesand to detect objects at or near the vehicle and in the predicted pathof the vehicle, such as to assist a driver of the vehicle in maneuveringthe vehicle in a rearward direction. The vision system includes an imageprocessor or image processing system that is operable to receive imagedata from one or more cameras and provide an output to a display devicefor displaying images representative of the captured image data.Optionally, the vision system may provide display, such as a rearviewdisplay or a top down or bird's eye or surround view display or thelike.

Referring now to the drawings and the illustrative embodiments depictedtherein, a vehicle 10 is equipped with an imaging system or visionsystem 12 that includes at least one exterior viewing imaging sensor orcamera, such as a rearward viewing imaging sensor or camera 14 a (andthe system may optionally include multiple exterior viewing imagingsensors or cameras, such as a forward viewing camera 14 b at the front(or at the windshield) of the vehicle, and a sideward/rearward viewingcamera 14 c, 14 d at respective sides of the vehicle), which capturesimages exterior of the vehicle, with the camera having a lens forfocusing images at or onto an imaging array or imaging plane or imagerof the camera (FIG. 1 ). Optionally, a forward viewing camera may bedisposed at the windshield of the vehicle and view through thewindshield and forward of the vehicle, such as for a machine visionsystem (such as for traffic sign recognition, headlamp control,pedestrian detection, collision avoidance, lane marker detection and/orthe like). The vision system 12 includes a control or electronic controlunit (ECU) or processor 18 that is operable to process image datacaptured by the camera or cameras and may detect objects or the likeand/or provide displayed images at a display device 16 for viewing bythe driver of the vehicle (although shown in FIG. 1 as being part of orincorporated in or at an interior rearview mirror assembly 20 of thevehicle, the control and/or the display device may be disposed elsewhereat or in the vehicle). The data transfer or signal communication fromthe camera to the ECU may comprise any suitable data or communicationlink, such as a vehicle network bus or the like of the equipped vehicle.

The camera and/or system of the present invention may utilize aspects ofthe cameras and systems described in U.S. Pat. Nos. 9,621,769;9,596,387; 9,277,104; 9,233,641; 9,077,098; 8,994,878; 8,542,451 and/or7,965,336, and/or U.S. Publication Nos. US-2009-0244361;US-2013-0242099; US-2014-0373345; US-2015-0124098; US-2015-0222795;US-2015-0266430; US-2015-0327398; US-2015-0365569; US-2016-0037028;US-2016-0243987; US-2016-0268716; US-2016-0286103; US-2016-0037028;US-2017-0054881; US-2017-0133811; US-2017-0201661; US-2017-0280034;US-2017-0295306; US-2017-0302829; US-2018-0098033; US-2019-0124238;US-2019-0124243 and/or US-2019-0306966, and/or U.S. patent applicationSer. No. 16/451,179, filed Jun. 25, 2019, now U.S. Pat. No. 10,899,275,Ser. No. 16/459,992, filed Jul. 2, 2019, now U.S. Pat. No. 10,676,041,Ser. No. 16/525,666, filed Jul. 30, 2019 and published as U.S.Publication No. US-2020-0033549, and/or Ser. No. 16/662,205, filed Oct.24, 2019 and published as U.S. Publication No. US-2020-0137926, and/orU.S. provisional applications, Ser. No. 62/913,288, filed Oct. 10, 2019,Ser. No. 62/866,662, filed Jun. 26, 2019, which are hereby incorporatedherein by reference in their entireties. It is envisioned that aspectsof the present invention may be applied to cameras and/or other types ofhigh precision sensors, such as Lidar or magnetic sensors or the like.Optionally, electrical connections in the camera may be established viamolded interconnect device (MID) technology, such as by utilizingaspects of the cameras described in U.S. Publication Nos.US-2018-0072239; US-2017-0295306 and/or US-2016-0037028, which arehereby incorporated herein by reference in their entireties.

Automotive cameras, particularly for autonomous vehicle control systems,must maintain precise lens-to-imager relative position throughout thefull range of operating temperatures. This is challenging because of thevarious camera assembly material CTEs (coefficients of thermalexpansion). The optical performance of the lens may also be acontributor.

Simulations have been performed on the mechanical and optical design topredict changes as accurately as possible. The actual assembly willoften still have a five or more microns lens-to-imager shift due tounforeseen behaviors with the components and optics. Further long-termcontrol is often unachievable.

Automotive cameras typically do not have features in them that allow foractive focus correction due to cost and robustness reasons. The camerafeatures that permanently fix the lens position relative to image sensormust therefore be static or predictive throughout the range ofanticipated environments. However, all materials experience some amountof temperature-driven expansion or contraction, and the expansion amountmay be different for the various materials used in the cameraconstruction. Quite often, an understanding of this effect ispredictable and can be compensated for with lens design orathermalization features. These effects are frequently considered as alinear stack of contributors in the direction of the optical axis. Aless predictable and less controllable source of change comes fromcompeting stresses in the off optical axis directions. A particular andcommon problem occurs when the amount of PCB thermal expansion does notmatch that of the supporting structure. PCB substrates (such assubstrates comprising glass fabric-reinforced laminates (FR-4), orceramic-based PCB materials such as Alumina or Aluminum Nitride orBeryllium Oxide, or polyimide or polytetrafluoroethylene (PTFE) or thelike) typically have a coefficient of thermal expansion (CTE) at orbelow 14×10⁻⁶ (° C.)⁻¹. Automotive camera enclosure materials, such asAluminum and Zinc alloys have CTEs that are above 20×10⁻⁶ (° C.)⁻¹,while most plastics have CTEs that are well above 30×10⁻⁶ (° C.)⁻¹. Thisstress condition between the materials may cause the features that holdthe PCB at the structure or housing or lens holder to yield and the PCBboard will then bend (such as shown in FIGS. 2-4 ). This bendingcondition causes either an over focused or under focused condition. Evenif the support structures do not yield, the PCB still will bend in thedirection that offers the least amount of resistance.

As can be seen with reference to FIGS. 2-4 , a camera 14 (such as one ofthe cameras 14 a-d disposed at the vehicle 10 in FIG. 1 ) has a printedcircuit board (PCB) 30 with a component 32 (such as an imager or imagingdevice or the like) disposed at a surface thereof. The PCB 30 is mountedto the front housing portion or lens holder 34 of the camera, such asvia two or more fasteners 36 that extend through apertures in thecircuit board substrate and threadedly engage threaded bores at asupport structure or attaching portion 34 a of the lens holder (such asa structure that circumscribes the lens holder and engages the PCBaround the imager). The PCB 30 is thus fixedly attached at the lensholder with the imager 32 optically aligned with the lens 38. As shownin FIG. 2 , when the camera is exposed to moderate temperatures, the CTEdifferences (between the CTE of the PCB substrate and the PCB of thelens holder or support structure) do not impact the focus of the camera.As shown in FIG. 3 , the PCB and imager are shown flexing or bendingdownward at the center region (between the side fixed points that areattached at a camera housing) away from the lens 38 when the camera isexposed to lower temperatures (such as below zero degrees Celsius orsuch as below −20 degrees C. or thereabouts, such as in a range of zerodegrees C. to −40 degrees C.). Such lower temperatures may cause thecamera body and structure to shrink more than the PCB substrate materialand force the PCB substrate to deflect. In the illustrated example, thesensor is moved away from the lens causing an under focus condition.Similarly, and with reference to FIG. 4 , the PCB and the imager areshown flexing or bending upward at the center region (between the sidefixed points that are attached at a camera housing) toward the lens 38when the camera is exposed to higher temperatures (such as above 40degrees C. or such as above 70 degrees C. or thereabouts, such as in arange of 40 degrees C. to 85 degrees C.). Such higher or extremetemperatures may cause the camera body and structure to expand more thanthe PCB substrate material and force the PCB to deflect. In theillustrated example, the sensor is moved closer to the lens causing anover focus condition.

One way to limit or reduce PCB stress and bending with temperaturechanges is to allow the PCB substrate to move freely in directionsperpendicular to the lens optical axis. This can be accomplished if someor all of the PCB through-holes for the mounting screws are oversizedand the clamp load is controlled. The use of a spring washer can be usedwith one or more of the mounting screws to consistently control clampload within a desirable range. This allows the PCB to move while it iskept firmly against the camera's support structure surface to maintainfocus.

For example, and with reference to FIGS. 5-7 , the camera 114 includesoversized PCB holes to allow for difference in thermal expansion betweenthe PCB 130 and the attaching portion 134 a of the lens holder orsupport structure 134. The screw or fastener 136 may have a springwasher at the screw head to control clamp force. With the PCB 130secured or fastened at the lens holder 134 at normal or nominal ornon-extreme temperatures (FIG. 5 ), the fastener 136 is generallycentrally located in the hole through the PCB substrate, and the imager132 is optically aligned with the optical axis of the lens 138. Thecircuit board substrate may be fastened to one portion of the supportstructure via a fastener through an oversized hole and another fastenerthrough a non-oversized hole or via fasteners through respectiveoversized holes.

As shown in FIG. 6 , low temperatures may cause the camera body toshrink more than the PCB material, whereby the PCB is allowed to shiftdue to the oversized hole (such that the fastener is toward an inboardregion of the oversized PCB hole), but the imager may become misalignedwith the lens. As shown in FIG. 7 , high temperatures may cause thecamera body to expand more than the PCB material, whereby the PCB isallowed to shift due to the oversized hole (such that the fastener istoward an outboard region of the oversized PCB hole), but the imager mayagain become misaligned with the lens. The system may accommodate theshift of the imager relative to the optical axis of the lens byadjusting the processing of the captured image data (to effectively movethe center of the active imaging area of the imager to be at the opticalaxis of the lens), or the camera may include an imager adjustmentmechanism to adjust the imager relative to the lens to accommodate suchshifting, such as by utilizing aspects of the cameras described in U.S.Publication No. US-2017-0048463, which is hereby incorporated herein byreference in its entirety.

Optionally, another approach to accommodate the different degrees ofexpansion or contraction is to provide elongated members (of the supportstructure or lens holder) that support the PCB and that can freely yieldwithout torqueing or stressing the PCB substrate. With this technique,the PCB substrate remains permanently secured to the lens holder orsupport structure to prevent potential long-term loosening aftermultiple thermal cycles. The imager also remains in alignment with theoptical axis of the lens. The supporting board members can also beshaped to yield readily in a particular direction while resisting inothers. A number of such supporting members may be arranged in a waythat provides enhanced axial stability as a system, while still allowingfor movement only toward or away from the board center.

For example, and with reference to FIGS. 8-12 , the lens holder 234 ofthe camera 214 may include elongated spaced apart posts 234 a thatextend from the lens holder or support structure (and may be formed aspart of the lens holder) and are shaped so that they can yield or flextoward and away from the board center (and the optical axis of the lens)and so that they provide side-to-side support of the PCB 230. This typeof arrangement allows for a different board CTE but also providesenhanced overall stability to the structure so that the PCB will notshift its position away from the center axis. The PCB substrate isattached at the distal ends of the posts 234 a, such as via an adhesive236 or the like (or such as via fasteners), with the imager 232optically aligned with the lens 238. The opposite ends of the posts areat or attached to the lens holder structure.

As shown in FIG. 8 , when the camera 214 is exposed to moderatetemperatures, the CTE differences (between the PCB and the supportstructure or lens holder) do not significantly impact the camera'sfocus. As shown in FIG. 9 , when the camera is exposed to lowtemperatures, which may cause the camera body to shrink more than thePCB material, the posts 234 a yield or flex slightly outward (radiallyoutward) to accommodate the lower degree of contraction of the PCBsubstrate (as compared to that of the lens holder). The posts atopposite sides of the PCB and imager flex the same so that the imagerremains aligned with the lens. As shown in FIG. 10 , when the camera isexposed to high temperatures, which may cause the camera body to expandmore than the PCB material, the posts 234 a yield or flex slightlyinward (radially inward) to accommodate the lower degree of expansion ofthe PCB substrate (as compared to that of the lens holder). The posts atopposite sides of the imager flex the same so that the imager remainsaligned with the lens.

Optionally, and with reference to FIGS. 13-15 , the posts 240 a may bepart of or extend from a separate part or attaching element 240 that isattached to the lens holder 234, such as via a threaded attachment atthe lens barrel or cylindrical lens support structure 234 b of the lensholder 234. The posts have their proximal ends attached at or formedwith the attaching portion of the element 240, with the circuit boardsubstrate attached at the distal ends of the posts, and with the postsextending generally parallel to a longitudinal axis of the lens barrel.

The post structure comprises a specific CTE lens athermalizationcomponent that is selected to provide the desired or appropriate degreeof flexing at different temperatures (i.e., is selected to have aparticular CTE and size). The lengths of the posts (the overall lengthof the posts and the length of the posts that extend beyond the threadedattaching portion) are selected or designed to provide the appropriatelens athermalization and to limit PCB bending. For example, the materialand dimensions selected for the posts may comprise a low CTE material ora high CTE material and is selected to offset the CTEs and lengths ofthe other materials to accommodate for expansion and contraction of theother components. Athermalization tuning (adjusting the imager relativeto the lens and along the optical axis of the lens) is possible bychanging the thread position of the posts on the lens holder/structure.

When plastic parts are molded, the CTE of the molded part is differentin the flow direction (the direction of flow of the resin materialduring the molding process) vs. the cross-flow direction. This imbalanceis affected by the percentage of glass fibers, or the length and shapeof the fibers, in the plastic molded part. The posts may be molded in aselected or specific orientation or with a selected or specific fiberloading direction to selectively have higher CTE in one direction offlexing of the posts and lower CTE in the other direction of flexing ofthe posts. Thus, for example, the posts may be formed such that thematerial composition of the posts allows for radial flexing of the postswhile limiting tangential flexing of the posts.

Therefore, the present invention provides for flexible support of thePCB at the lens holder or support structure, such that, as the PCB andlens holder expand/contract differently when exposed to varyingtemperatures (due to their different CTEs), the PCB does not bend orflex and thus maintains focus of the camera. The vehicular camera, whendisposed at a vehicle and during normal use, may experience operatingtemperatures between about −40 degrees C. to about 85 degrees C. Theposts support the PCB at the lens holder and, when the camera is exposedto or operates at higher or lower temperatures, flex or bend in a radialdirection (radially inward or outward toward or away from thelongitudinal axis of the lens barrel), while limiting flexing or bendingin another direction (circumferential or normal to the radial direction)to allow for temperature-driven expansion or contraction of the lensholder relative to the PCB substrate while maintaining alignment andfocus of the imager at the lens (by limiting or precluding flexing ofthe PCB substrate). The camera of the present invention thus maintainsfocus or enhances focus by the lens at the imager or imaging device, andlimits or reduces over or under focusing when the camera is exposed toor operates at extreme temperatures (e.g., below −20 degrees C. andabove 50 degrees C.).

The imaging sensor or camera may capture image data for image processingand may comprise any suitable camera or sensing device, such as, forexample, a two dimensional array of a plurality of photosensor elementsarranged in at least 640 columns and 480 rows (at least a 640×480imaging array, such as a megapixel imaging array or the like), with arespective lens focusing images onto respective portions of the array.The photosensor array may comprise a plurality of photosensor elementsarranged in a photosensor array having rows and columns. Preferably, theimaging array has at least 300,000 photosensor elements or pixels, morepreferably at least 500,000 photosensor elements or pixels and morepreferably at least 1 million photosensor elements or pixels. Theimaging array may capture color image data, such as via spectralfiltering at the array, such as via an RGB (red, green and blue) filteror via a red/red complement filter or such as via an RCC (red, clear,clear) filter or the like. The logic and control circuit of the imagingsensor may function in any known manner, and the image processing andalgorithmic processing may comprise any suitable means for processingthe images and/or image data.

For example, the vision system and/or processing and/or camera and/orcircuitry may utilize aspects described in U.S. Pat. Nos. 9,233,641;9,146,898; 9,174,574; 9,090,234; 9,077,098; 8,818,042; 8,886,401;9,077,962; 9,068,390; 9,140,789; 9,092,986; 9,205,776; 8,917,169;8,694,224; 7,005,974; 5,760,962; 5,877,897; 5,796,094; 5,949,331;6,222,447; 6,302,545; 6,396,397; 6,498,620; 6,523,964; 6,611,202;6,201,642; 6,690,268; 6,717,610; 6,757,109; 6,802,617; 6,806,452;6,822,563; 6,891,563; 6,946,978; 7,859,565; 5,550,677; 5,670,935;6,636,258; 7,145,519; 7,161,616; 7,230,640; 7,248,283; 7,295,229;7,301,466; 7,592,928; 7,881,496; 7,720,580; 7,038,577; 6,882,287;5,929,786 and/or 5,786,772, and/or U.S. Publication Nos.US-2014-0340510; US-2014-0313339; US-2014-0347486; US-2014-0320658;US-2014-0336876; US-2014-0307095; US-2014-0327774; US-2014-0327772;US-2014-0320636; US-2014-0293057; US-2014-0309884; US-2014-0226012;US-2014-0293042; US-2014-0218535; US-2014-0218535; US-2014-0247354;US-2014-0247355; US-2014-0247352; US-2014-0232869; US-2014-0211009;US-2014-0160276; US-2014-0168437; US-2014-0168415; US-2014-0160291;US-2014-0152825; US-2014-0139676; US-2014-0138140; US-2014-0104426;US-2014-0098229; US-2014-0085472; US-2014-0067206; US-2014-0049646;US-2014-0052340; US-2014-0025240; US-2014-0028852; US-2014-005907;US-2013-0314503; US-2013-0298866; US-2013-0222593; US-2013-0300869;US-2013-0278769; US-2013-0258077; US-2013-0258077; US-2013-0242099;US-2013-0215271; US-2013-0141578 and/or US-2013-0002873, which are allhereby incorporated herein by reference in their entireties. The systemmay communicate with other communication systems via any suitable means,such as by utilizing aspects of the systems described in InternationalPublication Nos. WO 2010/144900; WO 2013/043661 and/or WO 2013/081985,and/or U.S. Pat. No. 9,126,525, which are hereby incorporated herein byreference in their entireties.

The system may utilize sensors, such as radar or lidar sensors or thelike. The sensing system may utilize aspects of the systems described inU.S. Pat. Nos. 9,753,121; 9,689,967; 9,599,702; 9,575,160; 9,146,898;9,036,026; 8,027,029; 8,013,780; 6,825,455; 7,053,357; 7,408,627;7,405,812; 7,379,163; 7,379,100; 7,375,803; 7,352,454; 7,340,077;7,321,111; 7,310,431; 7,283,213; 7,212,663; 7,203,356; 7,176,438;7,157,685; 6,919,549; 6,906,793; 6,876,775; 6,710,770; 6,690,354;6,678,039; 6,674,895 and/or 6,587,186, and/or International PublicationNos. WO 2018/007995 and/or WO 2011/090484, and/or U.S. Publication Nos.US-2018-0231635; US-2018-0045812; US-2018-0015875; US-2017-0356994;US-2017-0315231; US-2017-0276788; US-2017-0254873; US-2017-0222311and/or US-2010-0245066, which are hereby incorporated herein byreference in their entireties.

Changes and modifications in the specifically described embodiments canbe carried out without departing from the principles of the invention,which is intended to be limited only by the scope of the appendedclaims, as interpreted according to the principles of patent lawincluding the doctrine of equivalents.

The invention claimed is:
 1. A vehicular camera, the vehicular cameracomprising: a camera housing comprising a first portion and a secondportion joined to the first portion; wherein the first portion of thecamera housing accommodates a lens, and wherein the first portion of thecamera housing comprises an attaching portion having a first coefficientof thermal expansion (CTE); a circuit board comprising circuitrydisposed at a circuit board substrate having a first side and a secondside opposite the first side and separated from the first side by athickness of the circuit board substrate, the circuit board substratehaving a second CTE that is different from the first CTE; wherein thecircuitry comprises an imager disposed at the first side of the circuitboard substrate, and wherein the imager comprises an imaging arrayhaving at least one million photosensors arranged in rows and columns;wherein the circuit board substrate is attached at the attaching portionof the first portion of the camera housing; wherein, when the vehicularcamera is operated at an operating temperature greater than 50 degreesC., the attaching portion expands a greater degree than the circuitboard substrate; and wherein, when the vehicular camera is operated atan operating temperature below −20 degrees C., the attaching portioncontracts a greater degree than the circuit board substrate.
 2. Thevehicular camera of claim 1, wherein the lens is accommodated by a lensbarrel of the first portion of the camera housing.
 3. The vehicularcamera of claim 1, wherein the circuit board substrate is attached atthe attaching portion of the first portion of the camera housing via atleast one fastener.
 4. The vehicular camera of claim 3, wherein the atleast one fastener threadedly engages the attaching portion to attachthe circuit board substrate to the attaching portion.
 5. The vehicularcamera of claim 1, wherein the circuit board substrate is attached atthe attaching portion of the first portion of the camera housing via aplurality of fasteners.
 6. The vehicular camera of claim 1, wherein thesecond CTE of the circuit board substrate is less than the first CTE ofthe attaching portion of the first portion of the camera housing.
 7. Thevehicular camera of claim 1, wherein the attaching portion comprisespart of an attaching element that is threadedly attached at the firstportion of the camera housing.
 8. The vehicular camera of claim 7,wherein the attaching element is threadedly adjusted at the firstportion of the camera housing to adjust the circuit board substrate andthe imager relative to the lens along a longitudinal axis of the lens.9. The vehicular camera of claim 1, wherein the first portion of thecamera housing comprises metal.
 10. The vehicular camera of claim 1,wherein the attaching portion comprises a polymeric structure.
 11. Thevehicular camera of claim 1, wherein the attaching portion is configuredto join the first portion of the camera housing with the second portionof the camera housing.
 12. The vehicular camera of claim 1, wherein theattaching portion comprises a plurality of posts extending parallel to alongitudinal axis of the lens, and wherein the posts are spaced apartaround the longitudinal axis of the lens.
 13. The vehicular camera ofclaim 12, wherein the posts are separate from and inward from exteriorwalls of the first portion of the camera housing.
 14. The vehicularcamera of claim 12, wherein flexing of the posts in a radial directionaccommodates temperature-induced expansion or contraction of the firstportion of the camera housing relative to the circuit board substratewithout flexing the circuit board substrate.
 15. The vehicular camera ofclaim 14, wherein each post of the plurality of posts is configured tonot flex in a direction normal to the radial direction.
 16. Thevehicular camera of claim 12, wherein the plurality of posts comprisesat least two posts at opposite portions of the circuit board substrate.17. The vehicular camera of claim 12, wherein the plurality of postscomprises at least four posts spaced circumferentially around thecircuit board substrate.
 18. The vehicular camera of claim 1, whereinthe vehicular camera captures image data for a surround view display ofa vehicle equipped with the vehicular camera.
 19. A vehicular camera,the vehicular camera comprising: a camera housing comprising a firstportion and a second portion joined to the first portion; wherein thefirst portion of the camera housing includes a lens barrel thataccommodates a lens, and wherein the first portion of the camera housingcomprises an attaching portion having a first coefficient of thermalexpansion (CTE); wherein the first portion of the camera housingcomprises metal; a circuit board comprising circuitry disposed at acircuit board substrate having a first side and a second side oppositethe first side and separated from the first side by a thickness of thecircuit board substrate, the circuit board substrate having a second CTEthat is different from the first CTE; wherein the circuitry comprises animager disposed at the first side of the circuit board substrate, andwherein the imager comprises an imaging array having at least onemillion photosensors arranged in rows and columns; wherein the circuitboard substrate is attached at the attaching portion of the firstportion of the camera housing; wherein, when the vehicular camera isoperated at an operating temperature greater than 50 degrees C., theattaching portion expands a greater degree than the circuit boardsubstrate; and wherein, when the vehicular camera is operated at anoperating temperature below −20 degrees C., the attaching portioncontracts a greater degree than the circuit board substrate.
 20. Thevehicular camera of claim 19, wherein the circuit board substrate isattached at the attaching portion of the first portion of the camerahousing via at least one fastener.
 21. The vehicular camera of claim 19,wherein the second CTE of the circuit board substrate is less than thefirst CTE of the attaching portion of the first portion of the camerahousing.
 22. The vehicular camera of claim 19, wherein the attachingportion is configured to join the first portion of the camera housingwith the second portion of the camera housing.
 23. A vehicular camera,the vehicular camera comprising: a camera housing comprising a firstportion and a second portion joined to the first portion; wherein thefirst portion of the camera housing includes a lens barrel thataccommodates a lens, and wherein the first portion of the camera housingcomprises an attaching portion having a first coefficient of thermalexpansion (CTE); a circuit board comprising circuitry disposed at acircuit board substrate having a first side and a second side oppositethe first side and separated from the first side by a thickness of thecircuit board substrate, the circuit board substrate having a secondCTE; wherein the second CTE of the circuit board substrate is less thanthe first CTE of the attaching portion of the first portion of thecamera housing; wherein the circuitry comprises an imager disposed atthe first side of the circuit board substrate, and wherein the imagercomprises an imaging array having at least one million photosensorsarranged in rows and columns; wherein the circuit board substrate isattached at the attaching portion of the first portion of the camerahousing; wherein the attaching portion is configured to join the firstportion of the camera housing with the second portion of the camerahousing; wherein, when the vehicular camera is operated at an operatingtemperature greater than 50 degrees C., the attaching portion expands agreater degree than the circuit board substrate; and wherein, when thevehicular camera is operated at an operating temperature below −20degrees C., the attaching portion contracts a greater degree than thecircuit board substrate.
 24. The vehicular camera of claim 23, whereinthe circuit board substrate is attached at the attaching portion of thefirst portion of the camera housing via at least one fastener.
 25. Thevehicular camera of claim 23, wherein the first portion of the camerahousing comprises metal.
 26. The vehicular camera of claim 23, whereinthe attaching portion comprises a polymeric structure.
 27. The vehicularcamera of claim 23, wherein the vehicular camera captures image data fora surround view display of a vehicle equipped with the vehicular camera.